add fix.latitude sprintf about neogps

[SlashDevin]

Use the utility function dtostrf.

I suggest searching the Arduino forum for "NeoGPS dtostrf"... there are many examples.

For your code, you would do something like

char tanggalDanJam[100];
if (fix.valid.location) {
  dtostrf( fix.latitude(), 8, 6, &tanggalDanJam[0] ); // or just tanggalDanJam
  uint8_t pos = strlen( tanggalDanJam ); // check how many chars were written into array
  tanggalDanJam[ pos ] = ','; // a comma after lat (before lon)
  pos++; // increment for comma character
  dtostrf( fix.longitude(), 8, 6, &tanggalDanJam[pos] ); // put lon after comma
}